Feeds

CERN data explains how Higgs heavies other matter

Standard Model hangs together as bosons fly apart

Intelligent flash storage arrays

Ever since the putative discovery of the Higgs boson in 2011, one of the next-big-thing searches in physics has been to confirm the mechanism by which the exotic particle imparts mass to other particles. Now, a team led by boffins from Brookhaven National Laboratory think they've contrived just such a test.

In work conducted at the LHC's ATLAS experiment, now at Arxiv, the ATLAS collaboration says it's detected the production of W boson pairs out of trillions of proton-proton collisions, and that the process they've observed helps explain the relationship of the Higgs boson to mass.

The Higgs was predicted by Peter Higgs et al, as the particle that gives gauge bosons (W+ W- and Z) their mass. To cite from Wikipedia, “At a critical temperature the Higgs field becomes tachyonic, the symmetry is spontaneously broken by condensation, and the W and Z bosons acquire masses”.

While the mechanism, like the Higgs boson, has been theorised since the first half of the 1960s, it's ferociously difficult to observe – which is why this is the first time it has been.

ATLAS experiment 'candidate event'

What's got ATLAS excited: a W-boson scattering candidate event

As Brookhaven's Marc-André Pleier, one of the leaders of the analysis, says in the laboratory's release: “Only about one in 100 trillion proton-proton collisions would produce one of these events … You need to observe many to see if the production rate is above or on par with predictions” (For those who understand the units used in particle physics, the researchers analysed the outcomes of 20.3 inverse femtobarns of data to get this result).

In the analysis, the ATLAS group was looking for pairs of W bosons, produced by electroweak interactions in the proton-proton collisions, which then scatter from each other, and in spite of the rarity of the interaction, 34 such events were identified.

That test yields only a 95 per cent confidence level, too low to proclaim a discovery but enough to get physicists excited at the data they'll collect when the revamped LHC (with more power) fires up. The 13 TeV setup will start collecting data in the northern 2015 spring, and will collect as much as 150 times as much data as the previous 8 TeV configuration.

“Now with the LHC data in hand, the measured rate agrees with the prevailing theory’s predictions and establishes a signal at a significance level of 3.6 sigma—strong evidence, according to Pleier”, the Brookhaven announcement states.

Pleier says the interactions so far observed match the rate of W-W production and scattering predicted by Standard Model physics – which is yet another arrow-to-the-knee for more exotic physics.

“We have a predicted fingerprint and we have the fingerprint we measure. If the fingerprints match, we know that the Higgs does its job of mass generation the way it should. But if it deviates, we know that some other physics mechanism is helping out because the Higgs alone is not doing what we expect.”

With the Higgs working as expected, “For the first time, we can rule out certain models or predictions that we could not before,” Pleier says. ®

Providing a secure and efficient Helpdesk

More from The Register

next story
SECRET U.S. 'SPACE WARPLANE' set to return from SPY MISSION
Robot minishuttle X-37B returns after almost 2 years in orbit
No sail: NASA spikes Sunjammer
'Solar sail' demonstrator project binned
LOHAN crash lands on CNN
Overflies Die Welt en route to lively US news vid
You can crunch it all you like, but the answer is NOT always in the data
Hear that, 'data journalists'? Our analytics prof holds forth
Experts brand LOHAN's squeaky-clean box
Phytosanitary treatment renders Vulture 2 crate fit for export
Carry On Cosmonaut: Willful Child is a poor taste Star Trek parody
Cringeworthy, crude and crass jokes abound in Steven Erikson’s sci-fi debut
Origins of SEXUAL INTERCOURSE fished out of SCOTTISH LAKE
Fossil find proves it first happened 385 million years ago
America's super-secret X-37B plane returns to Earth after nearly TWO YEARS aloft
674 days in space for US Air Force's mystery orbital vehicle
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Cloud and hybrid-cloud data protection for VMware
Learn how quick and easy it is to configure backups and perform restores for VMware environments.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.